Hi Steve,
Happy New Year!
If it's possible to add 978MHz receive to my device, I'll be happy...
We did 978MHz Rx as a dual band addition to 1090MHz Rx when SD/UAvionix were doing their original Weather Trials a few years back. A dead easy 'MOD' at the time simply by popping in a second SDR and either adding an extra antenna or using a 'splitter' to cover both Rx SDRs off a single 978* antenna (after Lee did the necessary dual-frequency software modification of course). Predictably, the trial 978MHz transmitters were all way down south, at SD HQ, Goodwood and a few sites round London including Redhill IIRC, so I only managed a couple of test flights on my way to and from Popham that year and wasn't particularly impressed at the time as it seemed to take ages to upload a full weather picture, then the trial was dropped, so we moved on and I took the extra SDR and splitter back out.
* Because of the relatively low 978MHz signal strength, we opted to use a tuned 978MHz antenna which still performed OK on 1090MHz
It should be fairly simple to go back to, though there might be an issue for those who are using PAW to provide 'ADSB Out' via transponders, since we are now using the 'spare' USB port for iGRID, but I'm sure we could sort something out if 978 becomes more relevant again.
Best Regards as always
Peter